Lithium-aluminum base filler alloy with optional silicon



United States Patent ice 3,272,624 LITHIUM-ALUMINUM BASE FILLER ALLOY WITH OPTIONAL SILICON Joseph F. Quaas, Island Park, N.Y., assignor to Eutectic Welding Alloys Corporation, a corporation of New York No Drawing. Filed May 23, 1963, Ser. No. 282,567 3 Claims. (Cl. 75-138) This invention relates to an aluminum alloy for joining and filling applications and it more particularly relates to a self-fluxing form of such an alloy. No flux coated aluminum base alloys are available for joining and filling purposes because the available fluxes are so reactive that they would prohibitively shorten shelf life. Conventional separately applied fluxes for depositing aluminum include chlorides and fluorides which must be completely removed from the joint area to prevent serious corrosion.

An object of this invention is to provide a self-fluxing type of aluminum base joining and filling alloy.

In accordance with this invention an aluminum filler alloy includes an amount of lithium ranging from 0.005 to 0.010% by weight which deoxidizes the deposited alloy system, actively fluxes the parent material during deposition and improves its wettability and the fluidity of the deposit. Amounts of silicon ranging from zero to 18% by weight may also be added to improve the aforementioned depositing action.

The aforementioned ranges and some examples of this invention are recited in the following table:

Range in Examples Constituents Percent by Weight Lithium 0. 00m. 010 0. 075 0. 075 0. 010 Silicon 0-18. 0 0 5 Aluminum Balance Balance Balance Balance 3,272,624 Patented Sept. 13, 1966 This filler alloy can be extruded in wire form or cast in molds in diameters ranging from to It can be applied by many conventional processes including carbon arc, oxy-acetylene and inert arc. The lithium additive makes the deposited alloy remarkably self-fluxing and deoxidizing. The lithium oxide formed during deposition also highly promotes fluidity and wettability. The labor saved in avoiding the necessity of applying a corrosive flux and removing it is highly significant because even with the utmost of care it is extremely ditficult to remove all flux residues from .the joint area. These flux residues of the chloride and fluoride type are extremely corrosive and require thorough cleaning in a hot water solvent and subsequent neutralization, such as by application of bicarbonate of soda.

What is claimed is:

1. An aluminum base filler alloy consisting essentially of from 0.005 to 0.010 percent by weight of lithium and the balance aluminum.

2. The aluminum base filler alloy of claim 1 which contains additionally up to 18 percent by weight of silicon.

3. A filler alloy as set forth in claim 1 including 01-18% by Weight of silicon.

References Cited by the Examiner UNITED STATES PATENTS 3,073,720 1/1963 Mets 138 3,081,534 3/1963 Bredzs 75-148 FOREIGN PATENTS 629,048 9/ 1949 Great Britain.

DAVID L. RECK, Primary Examiner.

R. O. DEAN, Assistant Examiner. 

1. AN ALUMINUM BASE FILLER ALLOY CONSISTING ESSENTIALLY OF FROM 0.005 TO 0.010 PERCENT BY WEIGHT OF LITHIUM AND THE BALANCE ALUMINUM. 